I admit it. I’m guilty of querying too soon, which we all know is one of the top reasons why a query is rejected. When I first began querying I was absolutely certain that my query was as perfect as it could be. Within a few days I’d sent out 12 or so queries all with the same mistakes, misspelling lent, and confusing than with then. How embarrassing. I even entered a few contests with these mistakes.
Thankfully, I eventually caught these errors with the help of my CP’s, but that still didn't make up for those queries that I sent out. The moral of the story is never query on a whim. Before you send that first query out be certain that it’s as polished as it can be. I think it helps to have more than one person have a look at it also because sometimes even your critique partner can miss things.
Now some agents are forgiving, and will overlook the simplest grammar or spelling error, but double checking will certainly keep those cringe worthy moments at bay. I did have a slight query flub just this week, but thank God it wasn't anything too bad.
Have you made any query blunders?